Prepared statement doesn't revalidate after table schema changes

Having simple table:

CREATE TABLE test1 (
  key TEXT,
  value TEXT,
  PRIMARY KEY (key)
);

I prepare following statement:

SELECT * FROM test1;

I run queries based on the statement which returns expected results.
Then I update schema definition like this:

ALTER TABLE test1 ADD value2 TEXT;

I populate the "value2" values and use the same statement again. The results returned by the same query don't include "value2". I'm sure it is not cached in the driver/application because I was starting new process after changing schema.

It looks to me like a bug. Please correct me if it works like this on purpose.

I'm using ruby cql driver but I believe it is not related.